Telephone-exchange system.



Patented Feb. 15, 1916,

C. L. GUODRUM.

//7 ve fl/o r.- C/mr/es L. 6004/0/27.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION mm JULY 915,,

CHARLES L. GDODEUM, (31? NEW YGRK,

** S FATENT @FFIQE.

ASSIQHGR, BY \VESTEEN ELE JTRYG COMPANY, INCOBPGRAT MESNE ASSIGIEMENTS, TQ

351.13, A CORZP'ORATION GE NEW YGRK.

Specification 01' Letters Patent.

Patented Fob. i5, 1916.

Application filed July 23, 1915. Serial No. 41,480.

1'?) all whom it may concern.

Be it known that 1, CHARLES L; Goon- RUM, a citizen of the United States, residing at New York, in the county of New York a andv State of N cw York, have invented certain new and useful Improvements in Telcphoneilxchnnge Systems, of which the 01 lowing is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems employing machine switcl1- ing, and particularly to systems or exchanges consisting of a number of ofiices. in trunking between orifices in such e changes, it is the practice to relay or repeat the impulses for setting the automatic switches at the distant 0 ice from the incoining office to the distant oliice. Due the conductive separation of the trunk cuit at the repeater by condensers, it is nec. essary to provide means for preventing such condensers from changing the character of the impii s relayed to the distant oilice to set the switches ,thereat, which they would otherwise do in discharging. Repeaters have been employed wherein relays disconneet the condensers from the trunk While the in'ipulses are being transmitted. After the swit use at the distnnhollice have been set, these relays again connect the condens erg to the trunk tocompletc the talking cir- Inis invention provides a highly efiicicnt repeater circuit \-herein the use of such relays, or their equivalents, is rendered unnecessary, and consists in inductively uniting, the incoming line with the outgoing trunk by a low capacity repeating coil, and including in circuit with the repeater windings on the incoming side a relay which is adapted to be operated intermittently by the sender, in accordance with the digits of the wanted number, to open and close e shunt circuit about a stepping relay at the (ii. .antolfice to set the switches there-at.

The invention will be more readily understood when rlescribed by reference to the accompanying drawing which illustrates only so much of a telephone systemes is necessary for c comprehension of the invcntion.

The calling subscriber at substantion A upon rcmovihg his receiver would set in motion a line finder whose brushes 23, 1?

anti terminals 18, such switches 22 only are shown, since well known in the art.

The calling subscriber is thus connected to a first selector which is then set by the sender S operated by the calling subscriber in the well-known brushes 15, 25

erutive rein-ti. Hunting in tline.

manner to step the of the first selector in opon to a group of trunks teroe ol'licc containing thewanted welhknown manner automatically pic'kout an idle one of these trunks. .Thcoperation of the apparatus up to this point is well known 8H0: therefore need not be described.

it may be of 1 end uctcr the type shown in U. S. Patent l3, terminal 1%, brush brush c-cruduct-or 24, brush 25, terminal 26, conductor 27,

lower left winding of re- The first selector would then inthe of repeatnesting coil it, conductors 28 and'29, right,

1Q its rightsrmnture and front contact Hi 3 at its .v s the following circuit to energizes slowrelay 28': free montiuctor {front contact pole of battery, relay pares a circuit for a slow relay 30. Relay at its out or armature on front contact closes the following circuit for stepping relay 6'.) at the distance switchgvhich in the present embodiment isn connector: free pole of battery, cuter armature and front conductor 33, lower nesting 0011 R, conducwinilings of rlsy 60, conductors 36 and -37. upper right winding of repeating 003i R to ground. The subscribers-t substn on A whiel nterrupts the line circu.

ngw gpgrates his sender S,

known me. it number of times, corresponding to the digit of the celled number involved in this particular selecting opera ticn.

leases its left 60 at the dis right armature and. of relay 19 to ground. This armature front 11 the well'-' lilniilllg of relay 10 to ground The relay contact pro-f Each time stepping-relay 10 recslling line is connected thereto, a slow relay adapted to be operated from the front con tact of said stepping relay and to apply cur rent to the outgoing section of said trunk, a stepping relay included in said trunk at the distant oilice energized by the closure of said circuit, a shunt circuit about said relay adapted to be closed upon each operation of said stepping relay in the incoming section, and an automatic switch adapted to he set by said stepping relay at the distant oflice.

4. In a telephone exchange system in com bination with telephone lines, offices wherein said lines terminate, a trunk circuit interconnecting said ofiices and divided into incoming and outgoing sections, a repeating coil uniting such sections, means for associating acalling line with the outgoing section of said trunk, a stepping relay 10 in the incoming section and adapted to be ener gized when a calling line is connected thereto, a slow relay 28' adapted to be energized from the front contact of said step ping relay and to apply current to the out going section of said trunk, a second slow relay 30 adapted to be operated from the back contact of said stepping relay, a stepping rela' 60 included in said trunk at the distant o co energized by the closure of said circui'v aunt about said relay controlled at front contacts of said slow relay 30 and stepping relay 1 and adapted to be closed each time the stepping relay is energized, and an automatic switch adapted to be set by said stepping relay (30 in the distant office.

5 In a telephone exchange system, the combination with a talking circuit divided into sections, means for inductively uniting said sections including feed coils and a source of current, an electromagnet included in one section of said circuit, a sender adapted to operate the same, an electromagnet included in the other section of said circuit, a shunt circuit about said last men tioned magnet controlled by said first mentioned magnet, and an automatic switch adapted to be set by the impulses so produced.

In witness whereof, I hereunto subscribe my name this 21st day of July A, 1)., 1915.

01 ES L. GOODRUM. 

